24 Jan
2021
24 Jan
'21
9:27 a.m.
So I found an RXV21 board in the pile of stuff here and popped it into
my 83. Crashes the system. It's an M8029 D board, and I see from this
site that you have to add a few traces and cut a few others to make it
work on an 11/73 or better.
http://www.chdickman.com/rx02/
I'll pop in an 11/23+ CPU just to test it, but is it really just putting
in two wires on the top of the board and cutting a total of three
traces? Looks simple enough...
C
24 Jan
24 Jan
4:41 p.m.
On 1/24/21 11:27 AM, Chris Zach via cctalk wrote:
So I found an RXV21 board in the pile of stuff here
and popped it into
my 83. Crashes the system. It's an M8029 D board, and I see from this
site that you have to add a few traces and cut a few others to make it
work on an 11/73 or better.
http://www.chdickman.com/rx02/
I'll pop in an 11/23+ CPU just to test it, but is it really just
putting in two wires on the top of the board and cutting a total of
three traces? Looks simple enough...
C
My M8029 stamped Rev F? has three jumpers and three trace cuts. It
matches the images posted in the link and works with an 11/73 ot 11/83.
But yes, it should be that simple.
There is a sharpied H on my card, which it is not the way DEC marked
these boards. The available field maintenance prints refer to this (no
G).? I don't know what the change was.
?? Jerry
6:11 p.m.
Ok. My guess is it throws off the cache on the 11/73 and above as it
works in an 11/23 (which is soooooo slow!).
I looked at the images, cut the traces, then soldered in two of the
wires. Board did not work on either the 11/83 or the 11/23+ CPU. However
when I looked closer I saw the tiny little wire down by the crystal and
the Q bus fingers. Put that in, and the board now works on the 11/23+,
will take the whole thing apart (again) and plug in the 11/83.
Fortunately I have the pdp11/83 configured with a Q bus memory board
(2-4mb) and a PMI memory board from an 11/84 placed in slot 2 (so the
11/83 will access it as Q Bus memory). Thus I could pull the 11/83 CPU
in slot 1 and pop the 11/23+ in. Aside from the exceptionally slower
speed and long boot times it works pretty well for testing.
Still need to get a 11/83 compatible PMI board, but the 11/84 ones work
as normal Q bus memory.
Thanks! Now I can read some of these RX02 disks and image them. I'm
guessing my BRU floppy that I generated with the RXV11 controller will
not boot on this RXV21 controller so I'll have to re-make that. And so
far it doesn't look like the disks made on that third party MXV21
controller are compatible with the RX02, should they be?
Chris
On 1/24/2021 7:41 PM, Jerry Weiss wrote:
On 1/24/21 11:27 AM, Chris Zach via cctalk wrote:
So I found an RXV21 board in the pile of stuff
here and popped it into
my 83. Crashes the system. It's an M8029 D board, and I see from this
site that you have to add a few traces and cut a few others to make it
work on an 11/73 or better.
http://www.chdickman.com/rx02/
I'll pop in an 11/23+ CPU just to test it, but is it really just
putting in two wires on the top of the board and cutting a total of
three traces? Looks simple enough...
C
My M8029 stamped Rev F? has three jumpers and three trace cuts. It
matches the images posted in the link and works with an 11/73 ot 11/83.
But yes, it should be that simple.
There is a sharpied H on my card, which it is not the way DEC marked
these boards. The available field maintenance prints refer to this (no
G).? I don't know what the change was.
?? Jerry
6:51 p.m.
On 1/24/21 8:11 PM, Chris Zach wrote:
Ok. My guess is it throws off the cache on the 11/73
and above as it
works in an 11/23 (which is soooooo slow!).
I looked at the images, cut the traces, then soldered in two of the
wires. Board did not work on either the 11/83 or the 11/23+ CPU.
However when I looked closer I saw the tiny little wire down by the
crystal and the Q bus fingers. Put that in, and the board now works on
the 11/23+, will take the whole thing apart (again) and plug in the
11/83.
Fortunately I have the pdp11/83 configured with a Q bus memory board
(2-4mb) and a PMI memory board from an 11/84 placed in slot 2 (so the
11/83 will access it as Q Bus memory). Thus I could pull the 11/83 CPU
in slot 1 and pop the 11/23+ in. Aside from the exceptionally slower
speed and long boot times it works pretty well for testing.
Still need to get a 11/83 compatible PMI board, but the 11/84 ones
work as normal Q bus memory.
Thanks! Now I can read some of these RX02 disks and image them. I'm
guessing my BRU floppy that I generated with the RXV11 controller will
not boot on this RXV21 controller so I'll have to re-make that. And so
far it doesn't look like the disks made on that third party MXV21
controller are compatible with the RX02, should they be?
Chris
Congrats!
Most of the third party controllers and drives are OS compatible with
the RX01 + RX02 format, provided you stick with Single Sided media.?
However, booting an OS with an RX01 controller handler (Interrupt
driven) will not succeed with an RX02 controller (DMA) or vice-versa.
The Double Sided media (RX03) make for interesting interchange stories.
I've seen double sided single density floppies. There are also
differences in how the controller vendors made disk handler
modifications for RT11.?? Many of these controllers would allow you to
perform a low level format, but only using vendor specific controller
commands. ? The DEC RX02 will only change the funky media density.
Remember that these are 18 bit controllers.?? Some operation systems can
work around this limitation, at the expense of CPU cycles.
? Jerry
7:04 p.m.
Most of the third party controllers and drives are OS
compatible with
the RX01 + RX02 format, provided you stick with Single Sided media.
However, booting an OS with an RX01 controller handler (Interrupt
driven) will not succeed with an RX02 controller (DMA) or vice-versa.
Ok, not a biggie, I can just VMR a new RX01 compatible disk with a DY:
boot driver in RSX11M+. Really there are two reasons for the RX drive:
Boot BRUSYS so I can backup/restore the system to TK50 tapes, and build
disks for the PDT11/150.
Well there is a third reason: I have here a box full of floppies that
include a full install set of TSX11+. This is 5.1c with a full license.
These are "double sided" in that there are two sector holes in each disk
so you can flip them over and have the sector pulse light work.
There is also SaturnBase, SaturnCalc, and SaturnGraph, 3.0 with a 3.0k
upgrade/patch disk.
Not sure if these exist elsewhere but I could make copies now with the
pdp11gui and finally slurp them into images. Do these already exist in
archives? Before putting these in I'd make sure to clean the heads and
everything so they don't take any damage.
The Double Sided media (RX03) make for interesting
interchange stories.
I've seen double sided single density floppies. There are also
differences in how the controller vendors made disk handler
modifications for RT11.?? Many of these controllers would allow you to
perform a low level format, but only using vendor specific controller
commands. ? The DEC RX02 will only change the funky media density.
Yah. I think Solarex used the MXV21 controller from MTI and it seems to
have its own unique format and an "FD:" driver. Which means I would be
stuck with RT11 4.0 which kinda sucks so why not
Remember that these are 18 bit controllers.?? Some operation systems can
work around this limitation, at the expense of CPU cycles.
Indeed. It's pointless to use them with RSX11 unless as I said to do a
boot disk for tape backup/recovery. But I started out on RX01's way back
when so I do have a bit of a soft spot in my head for them....
CZ
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